Specific Aims The aims of the core are: To provide statistical and data management support for the Program Project, focused on protocol design, data analysis, and manuscript support or the Program Project, focused on protocol design, data analysis and manuscript preparation. Data management systems are in place and new ones will de developed as necessary to assures that high quality data re available in a timely fashion for appropriate analyses. Complex statistical functions are accomplished in the Statistical Core using the resources described below which are not accessible for the many computer functions required to operate our large and diverse laboratory program. A minicomputer with a powerful database system (System 1032, CompuServe Data Technologies, Cambridge, MA) is currently in place and integrates all of the different aspects of our laboratory program.